/**
* Renders a single collapsible item group
* @param string $header a label of the item group [[items]]
* @param array $item a single item from [[items]]
* @param integer $index the item index as each item group content must have an id
* @return string the rendering result
* @throws InvalidConfigException
*/
public function renderItem($header, $item, $index)
{
if (array_key_exists('content', $item)) {
$id = $this->options['id'] . '-collapse' . $index;
$options = ArrayHelper::getValue($item, 'contentOptions', []);
$options['id'] = $id;
Html::addCssClass($options, ['widget' => 'panel-collapse', 'collapse' => 'collapse']);
$encodeLabel = isset($item['encode']) ? $item['encode'] : $this->encodeLabels;
if ($encodeLabel) {
$header = Html::encode($header);
}
$headerToggle = Html::a($header, '#' . $id, ['class' => 'collapse-toggle', 'data-toggle' => 'collapse', 'data-parent' => '#' . $this->options['id']]) . "\n";
$header = Html::tag('h4', $headerToggle, ['class' => 'panel-title']);
if (is_string($item['content']) || is_object($item['content'])) {
$content = Html::tag('div', $item['content'], ['class' => 'panel-body']) . "\n";
} elseif (is_array($item['content'])) {
$content = Html::ul($item['content'], ['class' => 'list-group', 'itemOptions' => ['class' => 'list-group-item'], 'encode' => false]) . "\n";
if (isset($item['footer'])) {
$content .= Html::tag('div', $item['footer'], ['class' => 'panel-footer']) . "\n";
}
} else {
throw new InvalidConfigException('The "content" option should be a string, array or object.');
}
} else {
throw new InvalidConfigException('The "content" option is required.');
}
$group = [];
$group[] = Html::tag('div', $header, ['class' => 'panel-heading']);
$group[] = Html::tag('div', $content, $options);
return implode("\n", $group);
}